The invention relates to a remote-controlled access control device, in particular for a motor vehicle, and a transponder which is configured for it.
German Patent DE 43 29 697 C2 discloses a remote-controlled access control device. A stationary transceiver unit, disposed for example in a motor vehicle, transmits an interrogation code signal when a triggering device (for example a door handle) is activated. The signal is received by a transponder which is carried by the user and is answered with a response code signal. The transceiver unit compares the received response code signal with a stored reference code signal and, when they correspond, enables access, i.e. unlocks the motor vehicle door. The transponder may be configured in the form of a conventional key or as a chip card.
In such a system, there may, however, possibly be a problem in that the transponder is addressed without authorization by a nonauthorized transmitter which simulates the interrogation code signal and the transponder subsequently transmits the response code signal. Due to the relatively large range of such radio signals, this response code signal can possibly be received by the stationary transceiver device even if the legitimate carrier or user of the transponder is already at a greater distance from the object, for example the motor vehicle, which is to be controlled. In this case, access to the object is enabled without the legitimate user having caused the access or without the user receiving information on this unauthorized opening procedure. There is also a risk of an unauthorized access to an object if the response code signal of the transponder is recorded and copied without authorization, and this copied response code signal is then used to obtain access.
It is accordingly an object of the invention to provide a remote-controlled access control device which overcomes the above-mentioned disadvantages of the heretofore-known devices of this general type and which reduces the risk of an unauthorized unlocking procedure.
With the foregoing and other objects in view there is provided, in accordance with the invention, a remote-controlled access control device, in particular for a motor vehicle, including a triggering device; a stationary transceiver device connected to the triggering device, the stationary transceiver device transmitting an interrogation code signal in response to the triggering device being activated; a portable transponder configured to receive the interrogation code signal and having a manually activatable activation element, the portable transponder generating a code signal and transmitting, together with the code signal, a given information indicating whether the code signal is generated in response to the interrogation code signal or in response to the activation element being activated; and the stationary transceiver device receiving the given information together with the code signal and generating an unlocking signal based on an evaluation of the given information and based on a comparison of the code signal with an internal reference code signal.
In accordance with another feature of the invention, the portable transponder is configured such that the given information is formed as a part of the code signal.
In accordance with a further feature of the invention, the stationary transceiver device, after receiving the code signal and evaluating the code signal as a correct code signal, emits at least a further interrogation code signal, which may be different from the interrogation code signal, and wherein the portable transponder, in response to the at least one further interrogation code signal, transmits at least a further code signal, which may be different from the code signal, the stationary transceiver device receives and evaluates the at least one further code signal transmitted by the portable transponder.
In accordance with an added feature of the invention, the stationary transceiver device provides the at least one further interrogation code signal as a signal that is different from the interrogation code signal.
With the objects of the invention in view there is also provided, a remote-controlled access control device, including a triggering device; a stationary transceiver device connected to the triggering device, the stationary transceiver device transmitting an interrogation code signal in response to the triggering device being activated; a portable transponder configured to receive the interrogation code signal and having a manually activatable activation element, the portable transponder selectively transmitting a first code signal in response to the interrogation code signal and a second code signal in response to the activation element being activated; and the stationary transceiver device receiving one of the first and second code signals and generating an unlocking signal based on an evaluation of the one of the first and second code signals.
In accordance with another feature of the invention, the stationary transceiver device stores or generates a first reference code signal for a comparison with the first code signal and a second reference code signal for a comparison with the second code signal, the stationary transceiver device generates the unlocking signal based on a comparison of one of the first and second code signals with the respective first and second reference code signals.
With the objects of the invention in view there is further provided, a portable transponder, in particular a motor vehicle key, which is configured for an access control device and which includes a manually activatable activation element; a control device connected to the manually activatable activation element, the control device generating a code signal and, together with the code signal, a given information indicating whether the code signal is generated in response to an interrogation code signal received from a stationary transceiver device or in response to the activation element being activated; and a portable transceiver connected to the control device, the portable transceiver being configured to receive the interrogation code signal from the stationary transceiver device and transmitting the code signal together with the given information.
With the objects of the invention in view there is additionally provided, a portable transponder including a manually activatable activation element; a control device connected to the manually activatable activation element, the control device selectively generating a first code signal in response to an interrogation code signal received from a stationary transceiver device and a second code signal in response to the activation element being activated; and a portable transceiver connected to the control device, the portable transceiver being configured to receive the interrogation code signal from the stationary transceiver device and transmitting one of the first and second code signals.
Depending on whether the transponder has received an interrogation code signal or whether the transponder is made to emit signals as a result of a manual activation of its activation element (actuation element), the transponder transmits different transmission signals to the stationary transceiver unit. These different transmission signals can be based on the distinction that, when an interrogation code signal is received and when the activation element is activated or actuated, the transponder always outputs the same base code signal, however, with an additional, added item of information, for example an identification or identifier, which indicates whether the transponder has been made to emit the code signal as a result of the reception of an interrogation code signal or as a result of the activation or manipulation of the activation element.
This additional information may not only be formed of an identification which has been added but may also be communicated in some other way, for example through the use of a different number of transmissions of the same code signal depending on whether an interrogation code signal had previously been received or else whether the activation element had been pressed. Such a configuration avoids the necessity of having to lengthen the code signal as such (by adding the identification) and having to generate this information on an updated basis at each transmission procedure. Instead, one and the same code signal can always be used, the cause of the transmission of the code signal being communicated by the transmission repetition number, in other words by how often the same code signal has been transmitted. For example, the configuration may be such that when the interrogation code signal is received, the code signal is transmitted twice in succession, while when the activation element is activated or actuated, the code signal is transmitted only once, or alternatively, three times.
In an alternative embodiment, provision may be made for carrying out an opening procedure only when there has been a multiple, for example triple, repetition of the interrogation and response code cycle. In this case, the interrogation code signal must be made available repeatedly at the correct time, which increases the level of security against an unauthorized opening procedure. If appropriate, the interrogation and/or response code signal can be changed during the repetition of the interrogation and response code cycles, for example by a respective recalculation of the interrogation and/or response code signal which is to be newly transmitted, the recalculation being based on the previously transmitted interrogation and/or response code signal and on an internal is key which is known to the transponder and to the stationary transceiver unit.
Furthermore, when the transponder activation element is actively activated or manipulated, in each case a plurality of code signals may be emitted by the transponder, preferably with an alternating coding. This increases the level of security against obtaining unauthorized access by copying the transponder code signals, since the signals then have to be respectively transmitted in the correct chronological order or time sequence and with the correct time interval or intervals. In this case, and in the case explained in the preceding paragraph, the stationary transceiver unit also checks the chronological position and chronological order or sequence of the code signals transmitted by the transponder, that is to say additionally checks a time criterion.
Alternatively it is also possible to configure the transponder in such a way that it can store (or generate) two different code signals, one of which is emitted in reaction to the reception of an interrogation code signal and the other in reaction to the activation or actuation of the activation element. The stationary transceiver unit checks the received code signal and, if appropriate, the additionally determined information, in which case, if it has previously transmitted an interrogation code signal it then expects, and makes available, a different item of information and/or a different reference code signal than in the event of an interrogation code signal not having been emitted beforehand. Only if the received code signal, and possibly the additional information, corresponds to the reference code signal which is currently made available and/or the currently expected information, does the transceiver device bring about the unlocking of the access, but otherwise it leaves the access blocked or disabled. If, in the case described at the beginning, the transponder has the interrogation signal applied or sent to it through the use of an unauthorized transmitter, it consequently transmits a code signal and/or an item of information which signals the preceding reception of an interrogation code signal to the stationary transceiver unit. Since the transceiver unit has, however, not emitted any such interrogation code signal and thus accepts only the code signal (or the associated additional information) associated with the activation of the transponder activation element, access remains blocked or disabled.
Access is enabled only if the transceiver device has itself actually previously transmitted the interrogation code signal. Likewise access is enabled if the code signal is transmitted on the basis of an activation of the activation element which is disposed at the transponder.
The transceiver device is configured in such a way that after an interrogation code signal is emitted a time window is opened for a brief time period of, for example, one second and only a response code signal which is received within this time window is accepted. The time window can be implemented by an internal timer, set to the corresponding time interval and being started when the interrogation code signal is emitted, the time window being closed again when the timer expires.
The invention can be used not only in motor vehicles but also generally in door locking systems, for example of houses and/or apartments or rooms.
The scope of the invention also includes a method for remote-controlled access in which signals are generated, transferred and evaluated in the manner described above.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a remote-controlled access control device, in particular for a motor vehicle, and a portable transponder which is configured for it, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.